U.S. Democratic presidential candidate Hillary Clinton is joined onstage by her husband former President Bill Clinton after she delivered her "official launch speech" at a campaign kick off rally in Franklin D. Roosevelt Four Freedoms Park on Roosevelt Island in New York City, June 13, 2015. REUTERS/Carlo Allegri

The Bill, Hillary & Chelsea Clinton Foundation and an associated charity refiled tax returns for six years with the U.S. Internal Revenue Service to amend their reporting of donations from foreign governments and other errors, the charities said on Monday.

The foundation refiled its Form 990 tax returns for 2010, 2011, 2012 and 2013, while the Clinton Health Access Initiative refiled its returns for 2012 and 2013 after Reuters discovered errors in the forms earlier this year.

The charities said they were not legally required to refile the forms and were only doing so in the interest of transparency following what the foundation’s president, Donna Shalala, called an “exhaustive review.”

The charities are best known for their work on health and environmental issues in the developing world, but have come under renewed scrutiny this year with Hillary Clinton’s decision to seek the Democratic Party’s nomination for the presidency in the election in November 2016.

Her critics, especially political rivals in the Republican Party, have said the charities’ reliance on millions of dollars from foreign governments creates conflicts of interests for a would-be U.S. president. They have also criticized the charities’ admitted failure to comply with an ethics agreement Clinton signed with Barack Obama’s incoming presidential administration in 2008 in order for her to become secretary of state.

In a letter to the foundation’s supporters, Shalala said the foundation brought in a new firm to examine its returns. While the firm, the tax division of law firm DLA Piper, found several types of errors, none of them were substantive, Shalala wrote.

“There is no change in our bottom line numbers: assets, liabilities, and net assets,” she wrote. “There is nothing to suggest that the Foundation intended to conceal the receipt of government grants, which we report on our website.”

Among other amendments, the foundation now reports receiving nearly $20 million in funds from governments, mostly foreign governments, between 2010 and 2013. The foundation had previously neglected to separately state its government funding as required on its original returns, although it continued to acknowledge foreign governments’ support throughout this period on its website and in its publications.

The charities pay no taxes on their donations, but are required to file annual returns with the IRS to maintain their tax-exempt status and to make them public to anyone who wants to see how they raise and spend money.

The amended forms also break out the charities’ income derived from the Clintons’ speeches to corporations, among other amendments.

Clinton severed her formal ties with her family’s charities upon announcing her presidential run in April, but her husband, former President Bill Clinton, and their daughter, Chelsea Clinton, retain active roles.